1. Field of the Disclosure
The present application relates to an organic light emitting display device. More particularly, the present application relates to an organic light emitting display device adapted to increase a content of filler and prevent contractive faults of pixels which can be caused by the intrusion of moisture.
2. Description of the Related Art
The display field for visually representing an electrical information signal has been rapidly developed with the spread of information society. In accordance therewith, a variety of flat panel display devices with features, such as slimness, light weight and low power consumption have been developed. Also, the flat panel display devices have been rapidly replacing the existing cathode ray tubes (CRTs).
As examples of the flat panel display devices, liquid crystal display (LCD) devices, organic light emitting display (OLED) devices, electrophoretic display (electric paper display (EPD)) devices, plasma display panel device (PDPs), field emission display (FED) devices, electroluminescence display devices (ELDs), elector-wetting display (EWD) devices, and so on can be introduced. Such flat panel display devices commonly include a flat display panel, which realizes an image, as a necessary component. The flat display panel is configured with a pair of combined substrates which face each other and have an inherent light emitting or polarizing material layer therebetween.
The organic light emitting display devices are self-illuminating display devices. As such, the organic light emitting display devices do not need a separate light source which is used in a liquid crystal display device. In accordance therewith, the organic light emitting display devices can become lighter and thinner. Also, the organic light emitting display devices have the features of wider viewing angle, superior contrast, and lower power consumption than those of the liquid crystal display devices. Moreover, the organic light emitting display devices can be driven by a low direct-current voltage and provide a high speed response. Furthermore, the organic light emitting display devices can well resist external impacts and be used in a wide temperature range because of having solid components.
In the organic light emitting diode display device, some electrodes can be damaged by external oxygen and moisture. As such, light can be emitted from some pixel regions. In other words, the external oxygen and moisture greatly deteriorate the device and reduce the lifespan of the organic light emitting diode display device. Therefore, it is very important to package the organic light emitting element to reduce the external oxygen and moisture.
As a packaging method, an entire surface sealing process can be used in the organic light emitting diode display device. In order to protect organic light emitting elements from the intrusion of external moisture, the entire surface sealing process allows an element substrate provided with the organic light emitting elements to be combined with a sealing substrate by means of an adhesive layer which is formed on the entire surfaces of the element substrate and the sealing substrate. The adhesive layer can include filler corresponding to a moisture absorbent, in order to prevent the intrusion of external moisture.
The filler is necessary to protect the organic light emitting element, but has a property of expanding by moisture. If a content of the filler increases, the filler expands by moisture and applies stresses to the element substrate and the sealing substrate. In other words, the adhesive layer between the element substrate and the sealing substrate must be lifted up due to the expansion of the filler which is caused by moisture.
Such a lift defect can force cracks to be generated in the interior of the related organic light emitting display device. The cracks can be used as intrusion paths of external moisture, gas, etc. Due to this, contractive faults can be generated. In order to prevent the lift defect, the content of the filler can be decreased. In this case, it is very difficult to prevent the intrusion of moisture.